The solar powered lighting system of the present invention is particularly suitable for outdoor advertising signs, however, the system may be used in any lighting environment. Because the primary application of the herein described invention is for powering outdoor advertising signs, however, the invention will be described in conjunction therewith for explanatory purposes only. The power source used in the present invention is described in pending U.S. Application Ser. No. 80,405, filed Oct. 1, 1979, for Solar Power Supply by William E. Rogers.
Illuminated outdoor advertising signs have traditionally been powered by connection to the local electrical utility service. That involves, of course, hiring an electrician to make the appropriate electrical connections to such signs and also involves the recurring monthly charge for electricity used. It is desirable for both environmental and economic reasons to use an alternative to commercially produced electricity. Solar power offers such alternative.
Previous attempts at solar powered signs, however, have involved taking the low voltage output of photovoltaic panels and converting that low voltage to a higher voltage in order to power conventional illumination sources. In particular, prior experiments involved attempting to convert the direct current output of photovoltaic panels to alternating current of sufficient mangnitude to power conventional mercury vapor, neon or other types of lighting systems. Such attempts have generally failed because the voltage conversion involves energy loss and concomittant inefficiency. The herein described invention solves that problem by using a lighting system capable of being operated at the same direct current low voltage generated by conventional photovoltaic panels. For example, a sign illuminated with light emitting diodes requires the same low voltage generated by conventional photovoltaic panels. That type of system is inherently more efficient because voltage conversion is not required.
The present invention uses a solar power source designed to operate such a low voltage sign. Because the solar power source is entirely self-contained, no connection to a local electrical utility service is necessary and of course no commercially produced electricity need be used.